This invention relates to a novel method for the production of perfluoro-(N-vinylamine) compounds. More particularly, this invention relates to a method for producing, economically in high yields from readily available raw materials, perfluoro-(N-vinylamine) compounds which are useful as intermediates or macromolecular monomers for synthesis of fluorine-containing products such as surfactants, agricultural pesticides, and medicines.
In the perfluoro-(N-vinylamine) compounds represented by the following general formula: ##STR2## [wherein R.sub.1 and R.sub.2 independently stand for a perfluoroalkyl group, providing that the two groups may be coupled either directly or through the medium of an oxygen atom or a nitrogen atom and the two groups may form a five-member or six-member ring in combination with the nitrogen atom to which they are coupled] and a perfluoro-alkyl amino group is joined to either of the carbon atoms of a double bond. By using these perfluoro-(N-vinylamine) compounds as intermediates, therefore, various useful compounds containing the perfluoro-alkyl amino group can be produced.
By copolymerizing these compounds with other fluoro-olefins, it is possible to lower the degree of crystallinity of producing copolymers due to the incorporation of the bulky perfluoro-alkylamino group and allow them to acquire improved mechanical properties. These perfluoro-(N-vinylamine) compounds are highly useful as intermediates for synthesis and as sources for production of fluorine-containing polymers.
These perfluoro-(N-vinylamine) compounds have already been known to the art and have heretofore been produced by the following two methods.
The first method comprises subjecting a perfluoroalkyl amino radical and a suitable fluorine-containing olefin to addition reaction and subsequently subjecting the resultant adduct to a reaction for removal of hydrogen halogenide or a reaction for thermal decomposition thereby re-forming an unsaturated bond.
It is known that perfluoro-(N,N-dimethylvinylamine) (specification of U.S. Pat. No. 3,311,599), perfluoro(N-vinylmorpholine) ["Journal of Chemical Society, Perkin I., page 5 (1973)], and perfluoro-(N-vinylpiperidine) ["Journal of Chemical Society", (C), page 2608 (1968)] can be produced by this first method.
Since this method uses special compounds as starting materials, however, it entails difficulty in procuring the raw materials, complexity of procedure of the production, and deficiency of yield as problems yet to be solved.
The second method comprises converting recently developed perfluoro-carboxylic acid derivatives into perfluoro-(N-vinylamine) compounds by thermal decomposition. Specifically, methods for producing perfluoro-(N-vinylamine) compounds represented by the formulas (Ia) and (Ib) by respectively using as raw materials perfluoro-carboxylic acid derivatives represented by the general formulas (II) and (III) have been known (Japanese Patent Application SHO 60(1985)-162631 and SHO 60(1985)-162632 and U.S. Ser. No. 06/886608, for example. ##STR3## [wherein A stands for a chemical bond, CF.sub.2, O&lt;, or R--N (wherein R is a perfluoro-alkyl amino group), X has the same meaning as defined above, and X.sub.1 stands for F, perfluoro-alkoxy group, or OM (wherein M has the same meaning as defined above)].
This second method, however, exclusively uses the perfluoro-carboxylic acid derivatives represented by the general formulas (II) and (III) as raw materials. No other perfluoro-carboxylic acid derivative has been known to be usable in the reaction which is effected by the second method.